Objective To investigate the effects of simulated microgravity by rotary cell culture system (RCCS) on expression profiles of miRNA in mouse fibroblasts L929 cell line.Methods L929 cells were cultured in vitro and divided into simulated microgravity (SMG) group and normal gravity (NG) group according to the simple random method.Samples of two groups were collected on 7th day of culture and the total RNAs were extracted,labeled,and hybridized in sequence.Feature Extraction Software was used to collect the array images and get raw data,which were analyzed by Genespring Software.Differentially expressed miRNAs were identified and then validated by qRT-PCR.Target genes of differentially expressed miRNAs were predicted by the databases of Targetscan and microRNAorg,and the intersections of databases were identified as potential regulatory target genes.Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis were applied to determine the roles of these target genes.Relevant biological functions and/or signaling pathways of the regulated genes especially related with wound healing process were categorized based on their enrichments.Then integration predictions of the miRNA and mRNA expression profiles had been proposed to refine the functional miRNA-mRNA relationships.The miRNA-mRNA functional network and miRNA-mRNA control network were constructed.Results Four miRNA genes were up-regulated significantly including mmumiR-669j,-122-5p,-30a-3p,-6516-3p,among which mmu-miR-669j was up-regulated at 52.84 folds with the greatest significance (P ＜ 0.05).Seventeen miRNA genes were down-regulated significantly including mmu-miR-21a-3p,-miR-28a-5p,-218-5p,-210-3p,-miR-19a-3p,-miR-31-3p,and-miR-19b-3p,among which mmu-miR-28a-5p was down-regulated at 15.47 folds with the greatest significance (P ＜ 0.05).The qRT-PCR showed a high concordance with the microarray results (P ＜ 0.05).Target gene prediction and functional enrichment analysis suggested that a variety of biological processes and signaling pathways involved in wound repair were significantly enriched (P ＜ 0.05).Function network and regulation network of miRNA-mRNA covered all the differentially expressed miRNAs,which suggested that miR-21 a-3p and predicted target gene Smad3 might play an important role in wound healing under microgravity.Conclusions Simulated microgravity by RCCS can significantly affect the expression of stress-related miRNAs in mouse fibroblasts L929.The miRNA target gene prediction and functional enrichment analysis based on gene chip technology may provide theoretical basis for illustrating the mechanism and management of weightlessness stress injury.

Objective:To investigate the clinical effect of arthroscopic debridement combined with high lateral tibial osteotomy and Giebel plate internal fixation in the treatment of varus knee osteoarthritis.Methods:From January 2016 to June 2018, 78 patients (96 knees) with varus knee osteoarthritis in Beijing Delcony Orthopedic hospital were treated by arthroscopic debridement combined with closed lateral tibial osteotomy and Giebel plate internal fixation. The femoral tibial angle (FTA) and hospital for special surgery knee score (HSS) score of knee joint were compared before and after operation.Results:70 patients (86 knees) were followed up for 12 to 28 months, with an average of 22.4 months. Bone healing was achieved at the osteotomy site 8 to 14 weeks after operation. Pain symptoms were relieved or disappeared significantly. The force line of X-ray examination was maintained at the postoperative level. The average knee femoral tibial angle was 187.6°preoperatively and 172.5° postoperatively, which showed significant statistical difference ( P<0.05). HSS knee score criteria: excellent: 70 knees; good: 10 knees; medium: 4 knees; poor: 2 knees. The excellent and good rate was 93.0%. The HSS score increased from (69.0±3.6) before operation to (87.2±8.1) after operation, with significant difference ( P<0.05). Conclusions:Arthroscopic debridement combined with high lateral tibial osteotomy and Giebel plate internal fixation is a very good method for the treatment of varus knee osteoarthritis, which is worthy of further clinical application.